import java.util.Random;

public class DownloadWorker implements Runnable {

    private final ChunkStatus chunkStatus;
    private final DownloadConfig config;
    private final Random random;

    public DownloadWorker(ChunkStatus chunkStatus, DownloadConfig config) {
        this.chunkStatus = chunkStatus;
        this.config = config;
        this.random = new Random();
    }

    @Override
    public void run() {
        chunkStatus.setStartTimeMs(System.currentTimeMillis());

        double downloaded = 0;

        System.out.println("Chunk " + chunkStatus.getChunkId() + " started.");

        while (downloaded < chunkStatus.getChunkSizeMB()) {

            int delay = random.nextInt(
                    config.getMaxStepDelayMs() - config.getMinStepDelayMs() + 1
            ) + config.getMinStepDelayMs();

            try {
                Thread.sleep(delay);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }

            double amount = random.nextDouble() *
                    (config.getMaxStepDownloadMB() - config.getMinStepDownloadMB())
                    + config.getMinStepDownloadMB();

            downloaded = downloaded + amount;

            if (downloaded > chunkStatus.getChunkSizeMB()) {
                downloaded = chunkStatus.getChunkSizeMB();
            }

            chunkStatus.setDownloadedMB(downloaded);

            System.out.println("Chunk " + chunkStatus.getChunkId()
                    + ": " + downloaded + "/" + chunkStatus.getChunkSizeMB() + " MB");
        }

        chunkStatus.setCompleted(true);
        chunkStatus.setEndTimeMs(System.currentTimeMillis());

        System.out.println("Chunk " + chunkStatus.getChunkId() + " finished.");
    }
}